Physics of Music and Sound: Final Exam Review

True/False: In a vibrating string, a node is a position on the string where displacement is a minimum.

True

True/False: In a vibrating string system; the longer the string, the lower the fundamental frequency.

True

True/False: Refraction occurs when two waves add together either destructively or constructively.

False

Density is equal to:

Mass divided by volume

If an object weighs 10 pounds on Earth, it will also weight 10 pounds on the Moon.

False

True/False: A closed tube can never have a node in its exact center.

True

True/False: In an open tube resonator, a node is always present in the exact center of the tube.

False

What is the frequency of the wave being driven in the string below if the fundamental frequency is 100 Hz?

300 Hz

If two waves are constructively interfering, the phase difference between two waves is:

0 Degrees

Huygen's principle states that:

All parts of a wave consist of individual sources of spherical waves called wavelets.

If two waves are destructively interfering, the phase difference between the two waves is:

180 Degrees

True/False: A simple harmonic oscillator requires both an equilibrium position and a linear restoring force.

True

Which harmonic is being driven in the open pipe pictured below?

Third

True/False: There is always a displacement antinode at the closed end of a resonating air tube.

False

Which harmonic is being driven in the closed pipe pictured below?

Fifth

True/False: Sounds heard around corners sound "muffled" because higher frequencies are diffracted more easily than lower frequencies.

False

If the velocity and acceleration of an object are both in the same direction, the object is slowing down.

False

Velocity is _____________ divided by time.

Displacement

True/False: A standing wave is a traveling wave that is interferes with its reflection.

True

True/False: In a closed tube resonator, only odd harmonics are present.

True

Which of the following is not a transverse wave?

Sound Wave

Pressure is equal to:

Force divided by area

If an oscillation is damped, then its ___________ decreases with time.

Amplitude

Which of the following describes the wave behavior called refraction?

Wave fronts change direction when crossing the boundary between two different types of media.

If the driving frequency is equal to the natural frequency of an oscillator, we say that the system is:

Resonant

True/False: A mechanical wave requires a source and a medium through which to propagate.

True

Which of the following are units of velocity?

m/s

If a source of sound is moving away from you, the frequency of that sound will be:

Decreased

True/False: In an open or closed pipe, a displacement antinode always corresponds to a pressure node.

False

True/False: The speed of a wave in a rope is independent of the tension in the rope.

False

The inverse square law states that:

The existence of a wave does not affect the existence or properties of another wave.

True/False: The speed of a wave can be determined by dividing its wavelength by its frequency.

False

True/False: The standing wave in a vibrating string is a longitudinal wave.

False

True/False: The Doppler effect says that a sound source moving toward you will have a lower frequency than if it were not moving

False

True/False: Point sources of waves tend to produce plane waves.

False

The kilogram is a unit of:

Mass

True/False: The standing wave in an open pipe is a transverse wave.

False

True/False: If two tones are being played, one at 150 Hz and the other at 155 Hz, the beat frequency from these two tones is 50 Hz.

False

What general wave behavior enables sound to be heard around corners?

Diffraction

True/False: The Linear Restoring Force in a simple harmonic oscillator is always directed toward the equilibrium position.

True

Displacement is defined as a change in:

Position

True/False: There is always a pressure node at the closed end of a resonating air tube.

False

The superposition principle states that:

The existence of wave does not affect the existence or properties of another wave.

When a string is plucked, it resonates with frequencies that are all integer multiples of the fundamental frequency of the string. This group of frequencies is called a:

Harmonic Series

True/False: In a open tube resonator, only even harmonics are present.

False

True/False: The Doppler effect can be experienced with either a moving source or a moving observer.

True

Which of the following are units of force?

N

True/False: Reflections occurs when waves bounce off of a surface.

True

True/False: All Periodic Motion is considered to be Simple Harmonic Motion

False

Which harmonic is being driven in the string pictured below?

Fourth

Any periodic complex waves can be synthesized by addition of a sinusoidal fundamental and subsequent harmonics, each with the proper amplitude and phase. This theorem is called:

Fourier's Theorem

True/False: Lenz's Law states that the induced voltage in a coil due to a changing magnetic field will oppose the changing field.

True

One loud violin tends to sound different that ten violins playing in unison such that their combined intensity is the same as the single violin. This is due to:

Chorus

True/False: Broad, flat walls oriented parallel to one another in an auditorium can lead to sound shadows.

False

Which of the following factors does not affect the sound or timbre of a musical tone?

Relative phase of the harmonics

The place theory of hearing states that the perceived pitch of a sound depends on the place of a resonance along the:

Basilar membrane

True/False: The precedence effect states that sound emanating from a series of speakers will always sound as though it is a all emanating from the most distant speaker.

False

A microphone that produces signal due to the movement of either a permanent magnet or a wire coil is called a:

Dynamic Microphone

The intensity of the smallest sound that can be perceived by the ear is called:

Threshold of hearing

True/False: If two tones are played together and one of the tones is louder than the other, it is possible for the louder tone to mask the presence of the softer tone.

True

If members of an orchestra are having difficulty hearing one another on stage, the room is said to be suffering from poor:

Ensemble

True/False: If the volume of a room is increased, the reverberation time will tend to increase.

True

True/False: The harmonic spectrum of a triangle wave contains only the even numbered harmonics.

False

An electromagnetic loudspeaker makes use of:

A coil of wire, AC signal, & a permanent magnet.

What is an inharmonicity?

A condition in which overtones are not multiples of the fundamental frequency.

True/False: As the charged plates in a condenser microphone move close together, the voltage on the plates increase.

False

A "live" room has a long reverberation time. As a result, liveness is considered synonymous with:

Fullness

True/False: THe Just Noticeable Difference (JND) is the minimum perceived frequency difference for two tones played simultaneously.

False

The harmonics of a certain instrument are emphasized in a specific frequency range. This frequency range is called a:

Formant

True/False: As long as the same pitch is maintained, changing the vowel sound of a sung note has no effect on the harmonic spectrum.

False

True/False: Domed ceilings can focus sound and contribute to poor blend in a concert hall.

True

A microphone that produces signal due to the movement of charged plates is called a:

Condenser microphone

The law that states a changing magnetic field within a coil of wire induces an electrical voltage in the coil is:

Faraday's Law

True/False: Large balconies protruding into an auditorium can affect the perceived sound by causing flutter echoes

False

You want to play music through a speaker containing both a woofer and a tweeter. In order to maximize the quality of sound, you connect the speaker to a network such that high frequencies go through the tweeter and low frequencies go through the woofer. This is called a:

Crossover Network

What is an attack transient?

A rapidly changing wave shape at the beginning of a musical tone.

If members of an audience hear reflections that are widely spaced in time, the room is said to be suffering from poor:

Texture

Although a musical tone will cause a wide region of the inner ear to resonate, the perceived pitch of a tone is well defined by the peak of this resonance. This effect is called a:

Sharpening

In a direct current(DC) circuit, a resistor has resistance. However, in an alternating current (AC), a resistor has:

Impedance

True/False The effect of rapid, periodic changes in the pitch of a musical tone is called tremolo:

False

In an AC circuit, the impedance of an inductor increases as the frequency of the signal increases.

True

If you wanted to decrease the reverberation time in a room, you would:

Increase the amount of sound absorption by placing carpet or textiles on the surfaces of the room.

True/False: The following spectrum is most likely produced by a recorder.

False

In an auditorium designed for speaking, the most desirable room quality is:

Clarity

The resonant frequencies of a room depend on:

Speed of sound, width, length, and height of the room.

True/False: The inverse square law says that if the distance to an object increased by a factor of 2, the intensity of the sound from that object will increase by a factor of 4.

False

True/False: The timbre of a musical tone depends strongly on the relative amplitudes of the harmonics present in the tone.

True

Who's principle states that pressure in a fluid will be lower where the fluid is moving faster?

Bernoulli

True/False: Binaural beats involve the mixing of tones in the brain, with no physical mixing of the actual sound waves.

True

The rate at which energy is delivered by a sound wave is called:

Power

Sounds entering the inner ear resonate along a relatively wide region of the basilar membrane. This region is called the:

Critical band

True/False: A "tweeter" is a speaker that responds best to low frequencies.

False

True/False: Ohm's law of Hearing states that the perceived tone quality is determined by the relative amplitudes of the harmonics.

True

Pure vibrato is periodic changes in the ____________ of a musical tone.

Pitch

True/False: The harmonic spectrum of a pulse train contains all harmonics at the same amplitude.

True

An audience member is listening to an orchestra play on stage. Much to their dismay, they hear the instruments from one part of the stage to be much louder than instruments on other parts of the stage. The auditorium is then suffering from poor:

Blend

The ear responds to sounds in a way that is non-linear. As a result, what are produced in the ear when a tone is heard?

Aural harmonics

True/False: White noise can be used to produce a musical tone in a resonator.

True

What is unique about the resonance curve of a Helmholtz resonator?

It includes only one peak representing the first harmonic.

True/False: A room that has much longer reverberation times for low frequencies than high frequencies is said to be very brilliant.

False